1. Field of Invention
The present invention relates generally to improvements in new and existing chicken house structures and methods of operation which reduce air-borne contaminants, such as ammonia (NH3), methane (CH4), carbon dioxide (CO2) and hydrogen sulfide (H2S), emissions and pathogens including, but not limited to, salmonella, E-coli, coccidiosis, other bacteria strains and fungus/mold development, while concurrently improving carbon dioxide removal, meat bird performance, chicken manure removal, chick brooding and overall chicken welfare during the growing process.
The present invention also relates to chicken house structures and methods to integrate the raising of baby chicks (the first two weeks of growth) with the growth after the first two weeks in order to improve overall chicken production.
2. Background Information
The chicken growing industry is based on mass production and low margin in which production casualties or weight reduction that might be considered trivial in other commercial activities can be detrimental to production cost. The magnitude of the industry is evident from the fact that a typical chicken house (approximately 40 to 60 feet×500 to 600 feet) will house 25,000 to 45,000 birds per flock. At harvest time, a typical commercial chicken house can have a density of 0.8 square feet per chicken or 7.5 lbs/square foot. Each bird will have consumed an average of 1.8 lbs. of feed per pound of chicken and an average of 2.25 gallons of water per pound of chicken by harvest time. Forty percent of the feed and water is consumed during the last week of growth. Broilers are grown to an average of 5.5 lbs. and roasters to an average of 7.25 lbs. The total amount of manure deposited on the floor bedding during each growth cycle is approximately 150,000 lbs. The total amount of excreted water is approximately 50,000 gallons, which makes it impossible to achieve and/or maintain bedding dryness under existing chicken house conditions.
Wet manure and saturated bedding, along with the massive animal heat generated by so many birds, results in perfect environmental conditions for bacteria and fungus development. Unfortunately, the widespread use of evaporative coolers for reducing the temperature can be counterproductive in that it results in high humidity, which is also conducive to ammonia and pathogen production. As the bacteria feeds on the manure and multiplies, it produces large amounts of ammonia gas, as well as methane gas. Uric acid breakdown accounts for 60% to 75% of the ammonia and CO2 emissions. The use of ventilation systems for removing ammonia and other gasses is not a satisfactory solution since such use can have undesirable results such as the introduction of cold air into the facility during cold weather with minimal ventilation.
One of the main problems resulting from high levels of ammonia in the chicken house is a wider variation in the uniformity of the flock. The percentage of small chickens can be as high as ten percent (10%) or more, and such birds cannot recover from growth deprivation early in their life cycle due to the fact that they cannot compete for or reach the water and feeder systems, which are at an elevation to accommodate normal-sized birds in the flock. Another problem resulting from high ammonia levels is increased susceptibility to disease producing pathogens including, but not limited to, E-coli infection, infectious bronchitis, and New Castle Disease.
Research has demonstrated that ammonia levels at or above 50 ppm (parts per million) inhibit bird growth, creating a degree of weight loss in all of the birds, not just the stunted chickens. Such weight loss can be as much as a half-pound per bird during a typical seven-week growth period. In fact, ammonia levels as low as 25 ppm have been shown to diminish bird growth. High ammonia levels also create physical defects such as blindness in the birds. Needless to say, a reduction in the number and size of marketable birds in a flock can be significantly detrimental to production cost. Moreover, the financial damage to the producer resultant from the loss of mature birds goes beyond the lost sales due to the previously incurred cost of feeding the chickens.
As stated previously, decomposition of the uric acid contributes 60% to 75% of the ammonia emissions in the chicken house, and large amounts of growth-inhibiting carbon dioxide are also produced. The carbon dioxide is 50% heavier than air and collects in a layer which remains near the floor of the facility affecting the bird level environment. Moreover, the carbon dioxide is difficult to remove due to the fact that the exhaust ports in conventional facilities are typically located in elevated positions well above the carbon dioxide layer. Also, the density of the chickens in the chicken house reduces the ability to effect flushing of the carbon dioxide from the facility since the chickens occupy the same space on the floor of the facility as the carbon dioxide. The carbon dioxide gas concentration is also greater during the last week of growth because the chickens consume approximately 40% of their total feed and water requirements during this time period as they are achieving their genetic potential for growth. The size of the chickens as well as their high concentration per sq. ft. of floor space consequently makes it very difficult to properly flush carbon dioxide and any other gas trapped between and under the chickens.
At chicken harvesting collection time the bedding is saturated with wet manure, making it the perfect environment for high ammonia levels, salmonella, E-coli, coccidiosis, multiple bacteria strains, fungus/mold and other pathogens to develop and multiply. This problem is exasperated at collection time due to the fact that the feed and water lines are lifted to a high elevation out of reach of the chickens in preparation for the collection procedure. The chickens consequently then naturally feed from the contaminated bedding with the result frequently being significant contamination of the chickens by potential food borne pathogens, i.e., salmonella, E-coli, and campylobacter. 
Detection of ammonia would obviously permit steps to be taken in an effort to reduce the ammonia level; however, such steps are frequently not taken because many producers are unaware of low, but harmful, ammonia levels in their facilities. Such unawareness is due to the fact that the human nose loses olfactory sensitivity to ammonia after repeated or long-term exposure and the growers become incapable of detecting ammonia levels of 50 ppm or lower due to such deterioration. Controlled experiments have shown that 50 ppm ammonia will cause a half-pound weight loss in a typical seven-week broiler growth period.
Hazards and additional grower expense arising from ammonia and other air-borne contaminants present in poultry growth facilities are not limited to poultry since such contaminants also create substantial health hazards for workers in such facilities including coughing, eye-irritation, dyspnea, headaches, fatigue and behavioral changes resulting in lost work-days and increased health and insurance costs to the producer.